I. Field
The following description relates generally to wireless communications, and more particularly to employing flexible signaling of resources on a control channel in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various types of communication; for instance, voice and/or data can be provided via such wireless communication systems. A typical wireless communication system, or network, can provide multiple users access to one or more shared resources (e.g., bandwidth, transmit power, . . . ). For instance, a system can use a variety of multiple access techniques such as Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), Code Division Multiplexing (CDM), Orthogonal Frequency Division Multiplexing (OFDM), and others.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple access terminals. Each access terminal can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to access terminals, and the reverse link (or uplink) refers to the communication link from access terminals to base stations. This communication link can be established via a single-in-single-out, multiple-in-single-out or a multiple-in-multiple-out (MIMO) system.
MIMO systems commonly employ multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. A MIMO channel formed by the NT transmit and NR receive antennas can be decomposed into NS independent channels, which can be referred to as spatial channels, where NS≦{NT,NR}. Each of the NS independent channels corresponds to a dimension. Moreover, MIMO systems can provide improved performance (e.g., increased spectral efficiency, higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized.
MIMO systems can support various duplexing techniques to divide forward and reverse link communications over a common physical medium. For instance, frequency division duplex (FDD) systems can utilize disparate frequency regions for forward and reverse link communications. Further, in time division duplex (TDD) systems, forward and reverse link communications can employ a common frequency region so that the reciprocity principle allows estimation of the forward link channel from reverse link channel.
Wireless communication systems oftentimes employ one or more base stations that provide a coverage area. A typical base station can transmit multiple data streams for broadcast, multicast and/or unicast services, wherein a data stream may be a stream of data that can be of independent reception interest to an access terminal. An access terminal within the coverage area of such base station can be employed to receive one, more than one, or all the data streams carried by the composite stream. Likewise, an access terminal can transmit data to the base station or another access terminal.
Base stations commonly schedule uplink and downlink transmissions. For instance, a base station can allocate one or more resource blocks to be utilized when transferring downlink transmissions to a particular access terminal. By way of further illustration, the base station can allot one or more resource blocks to be employed for sending uplink transmissions from a given access terminal to the base station. Moreover, the base station can use a signaling scheme to notify access terminals concerning such resource block assignments. However, conventional signaling schemes designed to indicate to a particular access terminal that one or more resource blocks associated with uplink or downlink channel(s) are allocated to that particular access terminal oftentimes use significant amounts of overhead and/or can be inflexible. According to an example, common signaling techniques can use a bitmap structure where a respective bit corresponds to each resource block that can be allocated by a base station to an access terminal; thus, each bit can indicate whether or not the corresponding resource block is allocated to a given access terminal. When used in a broadband communication environment that operates over large bandwidths (e.g., relatively wide range of frequencies, . . . ), the number of bits used to signal resource block allocations to access terminals can become very large. Hence, significant overhead usage can hamper overall system performance and/or cause such signaling techniques to be impractical or infeasible.